Before her death in 2005, Hendrikje van Andel-Schipper of the Netherlands was the oldest woman alive. She lived to be 115 and three months old.

Surprisingly though, when she died, her brain was still in good shape, with no sign of Alzheimer's or any of the other diseases typically associated with old age. In fact, she seems to have been disease-free, according to the researchers charged with examining her remains.

So what caused her death? According to a report in New Scientist online, it might have to do with “stem cell fatigue” -- essentially, running out of the stem cells needed to keep us functioning.

Here’s the scoop.

Blood stem cells are what our bodies use to continually replenish our tissues. We humans are typically born with around 20,000 of these cells. But over time, they weaken and die out.

And it might be this process that ultimately limits how long a human being can live, even if he or she succeeds in evading every other possible cause of death.

"Once the stem cells reach a state of exhaustion that imposes a limit on their own lifespan,” reports New Scientist, “they themselves gradually die out and steadily diminish the body's capacity to keep regenerating vital tissues and cells, such as blood."

And then? Ultimately and inevitably, we die.

The VU University Medical Center researchers who studied Andel-Schipper’s remains said that at the time of her death, she had just two blood stem cells left. The rest had presumably burned themselves out.

It probably won’t be long before progressive healthcare organizations begin offering relatively young people the ability to remove and store stem cells for use later in life. And there will no doubt be plenty of takers, especially among those who have no belief in, or hope for, eternal life.

Of course, even if the entire process works perfectly, eventually those “saved” stem cells will wear themselves out. And their owners will once again find themselves standing on the brink of forever. Let’s hope that they will use all that extra time they think they’ve bought considering where they want to spend eternity, and making the decision that will guarantee them of a truly heavenly ever-after.